The present disclosure relates to aromatic carbonate polymers and blends rendered resistant to coloring caused by exposure to sterilizing irradiation. More particularly, this disclosure relates to aromatic carbonate polymers and blends containing cyclic aliphatic alcohol compounds that are effective for color stabilizing the polymers and blends.
Aromatic carbonate polymers are well-known engineering thermoplastics with an excellent balance of optical, physical, mechanical, and processing characteristics. Various grades of aromatic carbonate polymers are widely used in a range of medical applications because of the material's transparency, toughness, rigidity, heat resistance, dimensional stability, and moldability in intricate parts. Many medical devices produced from aromatic carbonate polymers for example, dialysis and anesthesia canisters, syringes, stopcocks, blood oxygenators, cardiometry reservoirs, intravenous connectors and accessories, blood filters, trocars, stopcocks, luer locks, Y-sites, catheters, trays, dental instruments, pipettes, glucose meters, inhalers and centrifuge bowls, require sterilization to help ensure product safety. One of the most popular medical sterilization techniques includes exposing the device containing an aromatic carbonate polymer to ionizing irradiation. However, exposure of the aromatic carbonate polymers to radiation causes color formation, e.g., yellowing of the aromatic carbonate polymer.
A variety of additives have been tried to retard color formation, e.g., yellowing, to aromatic carbonate polymers after exposure to sterilizing radiation. Some additives e.g., liquid additives have shown positive effects towards retarding discoloration of the polymer after radiation sterilization, but these additives have certain disadvantages. They have lower flash points and hence at least some part of the additives lost during processing and also potential hazard while extruding the aromatic carbonate polymers comprising the liquid additives at elevated temperatures.
Hence, there is a need for new additives for use with aromatic carbonate polymer compositions that are easier to incorporate into the composition and at the same time provide inhibition to color formation that occurs after exposure to sterilizing radiation.